Encapsulated synthetic liquid detergent and process for preparing the same



United States Patent 3,528,925 EN CAPSULATEI) SYNTHETIC LIQUID DETER-GENT AND PROCESS FOR PREPARING THE SAME Jacques Chapuis, RR. 2,Hemmingford, Quebec, Canada No Drawing. Filed Dec. 1, 1966, Ser. No.598,223 Claims priority, application Canada, Nov. 12, 1966, 975,413/66Int. Cl. Clld 1/12 U.S. Cl. 252161 12 Claims ABSTRACT OF THE DISCLOSURESynthetic liquid detergents containing less than 1% water and as littleas 0.15% water are encapsulated in gelatin. The detergent compositionfor encapsulation is obtained by azeotropic distillation of an anionicsurface active agent in a solvent followed by addition of a nonionicsurface active agent, heating until a homogeneous solution is obtainedand a further azeotropic distillation. The solvent is then removed andthe composition encapsulated.

FIELD OF THE INVENTION This invention relates to an encapsulated liquiddetergent. This invention also relates to a process for preparing anencapsulated liquid detergent. This invention also relates to a processfor preparing an encapsulated liquid detergent containing apredetermined quantity of active liquid detergent.

DESCRIPTION OF THE PRIOR ART Present liquid detergents sold commerciallyhave generally 20 to 40%, perhaps even 45% active material, balancewater, except for a very minor amount of alcohol. As a consequence,present marketing methods are bulky and use considerable shelf space inretailing outlets. Also, as will be apparent, the mark-up involved atthe several stages from production to retail is very uneconomical to thecustomer because of the large amount of water present.

Moreover, an inherent difficulty facing the customer resides in theproblem of measuringthe exact quantity of liquid detergent needed for agiven purpose.

The possibility of encapsulating liquid detergents in a self-dissolvingcapsule has been proposed to overcome some of these problems. However,until now, encapsulation of liquid soaps has been successful only in avery specialized field, ie, for perfumed oil. However, theseformulations are totally unacceptable in the field of liquid detergents.

SUMMARY OF THE INVENTION It is an object of the invention to provide aliquid detergent in capsule form. It is a further object of theinvention to provide, in capsules, a highly concentrated liquiddetergent composition that is clean, convenient to use and economical,containing a predetermined amount of active material. It is a furtherobject of the invention to provide a process for preparing saidencapsulated liquid detergent.

In accordance with the present invention, an encapsulated liquiddetergent is provided, having at least 85% activity and beingencapsulated in a water-soluble capsule e.g. gelatin. The capsuleobtained usually contains less than 1% moisture.

The product of the invention is obtained by preparing a composition by aprocess wherein, while the formation of a sodium salt is prevented, analkylarylsulfonic acid anionic surface active agent is dissolved in anorganic solvent comprising a compound forming an azeotrope with water;the mixture is dried; a nonionic surface active ICC agent is added, ifdesired; the mixture is heated under reflux until a homogeneous solutionis obtained and the solvent is removed. The resulting composition isthen encapsulated in gelatin.

In a specific embodiment, the synthetic detergent composition isobtained as follows:

(I) An anionic surfactant e.g. an alkylarylsulfonic acid is treated toremove as completely as possible any sulfonating agent employed in theproduction of the anionic surfactant such as acid or S0 and water whilepreventing the formation of the sodium salt and while being dissolved ina solvent such as benzene or toluene, which forms an azeotrope withwater. Preferred are alkylarylsulfonic acids wherein the alkyl groupcontains from 4 to 16 carbon atoms and the aryl group is benzyl,naphthyl or phenyl.

In a practical manner, the alkylarylsulfonic acid is dissolved in e.g.benzene, washing with water and with sodium bicarbonate, removing thewater layer and drying. Drying is conveniently effected in two steps,the first one consisting in drying over e.g. calcium chloride, thesecond one, by azeotropic distillation until all Water is removed.

(2) A mixture is made of the composition obtained in 1) with a nonionicsurfactant (e.g. alkylaryl polyalkylene glycol) and an alkanoalaminee.g. triethanolamine. This mixture is more conveniently made at about4045 C. For best results, a foam stabilizer is added (e.g. nonionicfatty acid alkanolamide) as well as small amounts of glycerine (whichimproves the physical condition of the capsule).

The mixture is then heated under reflux for approximately one hour, thatis until (1) the pH reaches 7-7.5 or about (2) the mixture ishomogeneous.

This is followed by a further azeotropic distillation to remove anywater contained, e.g., in the nonionic surfactant or in the foamstabilizer. The azeotropic distillation is continued until the productis practically anhydrous.

(3) The solvent is then removed from the product thus obtained. This isconveniently done by applying vacuum in the case of benzene.

(4) The product thus obtained is encapsulated in a water-soluble capsuleeg in gelatin.

As mentioned hereinbefore, formation of the sodium salt of the anionicsurfactant must be prevented as otherwise the surfactant wouldprecipitate. The sodium salt is formed at approximately pH 8. To retainthe pH below this limit, agents such as alkylamines or alkanolamines canbe used. Addition of alkanolamines also lowers the hardness of thesurface active agent. Preferred are alkanolamines or alkylamines havinga hydrocarbon radical containing from 2 to 6 carbon atoms such asethanolamine, diethanolamine, triethanolamine, dimethylamine ortri-methylamine.

DESCRIPTION OF PREFERRED EMBODIMENTS The invention will now be describedin further detail, with reference to the following non-limitingexamples, wherein parts are by weight unless otherwise indicated.

Example I gr. dodecylbenzenesulfonic acid are added to 200 cc. benzeneand the solution is washed twice with cc. water, then with 50 cc. of a5% solution of sodium bicarbonate, then again with 50 cc. water. Thewater layer is removed, dried over sodium sulfate or calcium chlorideand subjected to an azeotropic distillation. The benzene is then removedin vacuum and replaced with an equal amount of fresh benzene. Thesolution is heated to 40 C.45 C. and a solution of 37.5 gr. nonionicsur- 3 factant sold under the trademark Tergitol NPX (a nonionic nonylphenol polyethylene glycol having 10.5 mol of ethyl oxide, a cloud pointof 60-65 C., specific gravity /20 C.: 1.06, solidification temperature:57 C. and surface tension-0.10% aqueous solution at C.: 32.3 dynes/cm.)is added slowly with 1.0 gr. triethanolamine, stirred for 15 minutes and2 gr. laurylamide and 1.5% glycerine are added. The mixture is refluxedfor 1 hr., then, is subjected to an azeotropic distillation. The solventis evaporated in vacuum at 45 C., then 3% alcohol is added and thesolution is stirred for minutes at 45 C.50 C.

This synthetic detergent is ready for encapsulation.

Example II Part I.37.5 gr. of a nonionic surface active agent sold underthe trademark Triton X100 (octyl phenoxy polyethoxy ethanol by inserting9-10 moles of ethylene oxide) is heated to C. C. and 22.0 gr. oftriethanolamine is added.

Part II.To 45 gr. dodecylbenzenesulfonic acid is added 150 cc. benzene,the solution is washed with Water and then with a 5% solution of sodiumbicarbonate. This solution is then removed and the balance is washedagain with water. The water layer is then discarded and the remainder isdried over sodium sulfate or calcium chloride. The thus dried solutionis then subjected to azeotropic distillation, and, then, the benzene isreplaced by the same amount of fresh benzene. At 45 C.- C., under goodagitation, Part II is added to Part I. After this introduction isterminated, the mixture is refluxed for 1 hr. and then, the solvent isdistilled off at normal pressure. The resulting solution is subjected tovacuum for /2 hr. at 45 C., and at this temperature, a solution ofalcohol, alkanolamide and glycerine is added and stirred in for /2 hr.

This synthetic detergent is ready for encapsulation.

Example III A solution of 330 g. of tert-butylnaphthalene sulfonic acidin 600 ml. of benzene is Washed with a 5% sodium carbonate solution andseveral times with water in order to bring the pH to 5-6. The solutionis dried over sodium sulfate for 12 hrs. The solvent is removed underreduced pressure and replaced with dry benzene. A solution of 235 g. oftriethylamine in 200 ml. of benzene is added under eflicient agitationin 30 minutes at a temperature of 35 C.-40 C. The resulting solution isstirred for 30 minutes and treated in one portion, with a solution of 72g. of nonylphenylpolyethylene glycol in 100 ml. of benzene and 22 g. ofglycerol. After refluxing for 1 hr. the solvent is dried by anazeotropic distillation and the solvent removed at reduced pressure.Perfume (0.2%) and absolute alcohol (15 ml.) is then added. The pH ofthe solution (0.1%) is approximately 7.5.

Example IV To a solution of g. of octylphenylsulfonic acid in 200 ml. ofethylenedichloride previously Washed according to Example I or II isadded in 30 minutes a mixture of 12 g. of laurylethoxylate in 50 ml. ofethylenedichloride. Then 23 g. of diethanolamine are added in 30 minutesat a temperature of 30 C.35 C. The solution is then refluxed for 1 hr.,then, the solvent is removed under reduced pressure. 200 ml. of benzeneare added to the viscous solution and the solvent is dried by anazeotropic distillation and then removed at reduced pressure. 10' ml. ofabs. alcohol, 8 g. of glycerol and 0.2% of perfume are then added to themixture which is stirred vigorously for 30 minutes at 40 C.45 C. The pHof the resultant solution is approximately 7.7.

Example V Through a. solution of 200 ml. of toluene previously 6 t isbubbled 75 g. of trimethylamine. Then a solution of 42 g. ofnonylphenyl-sulfonic acid in 100 ml. of toluene is slowly added undervigorous agitation during a period of 1 hr. The temperature ismaintained at between 10 C.15 C. The resulting solution is stirred for30 minutes and the temperature is raised to 25 C., then treated in oneportion With a solution of 10 g. of nonylphenylpolyethylene glycol, 5 g.of glycerol and ml. of toluene. After refluxing for 1 hr., the solventis dried by an azeotropic distillation and the solvent removed atreduced pressure. 10 m. of abs. alcohol and 0.2% of perfume are addedand stirred until the viscous solution is homogeneous. The pH of theresultant solution is approximately 7.6.

The product of the invention has the following characteristics:

Stability in hard waterGood Stability in sea waterGood Effect of changeof temperature-When cooled to 0 C. and warmed to 40 C. for 24 hrs. theproduct remains homogeneous and stable.

Foaming ability20-22 ml.

The product, for encapsulation, must contain less than 1% Water,preferably less than 0.5%. By the process described hereinabove, it wasfound possible to obtain as little as 0.15% water in the product.

Alcohol and/or glycerine are preferably added to the synthetic detergentbefore encapsulation. Glycerine is a softening agent which also acts asa preservative or barrier for the gelatin capsule. Alcohol traditionallyacts as a binder between anionic and nonionic surfactants and is also,to a slight degree, a dehydrating agent. Both optional ingredients arerecommended since they facilitate the production of a homogeneousmixture and/or the encapsulation.

The encapsulation in gelatin of the products obtained as hereinbeforedescribed can be made in accordance with known methods. According to apreferred method, gelatin and, if desired, glycerine are first blended.Dyes can also be added if desired. The mass is then melted under a highvacuum to eliminate entrapped air. The liquid melted mass is then formedinto two continuous ribbons of gelatin which are then shaped and filledwith the liquid detergent described. The resulting filled halves of thecapsule are then sealed under temperatures not higher than 37 C. and thesealed capsules are washed with alcohol and dried.

I claim:

1. An encapsulated synthetic liquid detergent composition at leastactive, the synthetic liquid detergent component of said compositionconsisting essentially of. by weight,

(a) 33-65% alkylarylsulfonic acid wherein the alkyl group contains from4 to 16 carbon atoms and the aryl group is benzyl, naphthyl or phenyl,

(b) 836.5% nonionic surface active agent, and

(0) 2059% alkanolamine or alkylamine wherein the alkyl or alkanol groupcontains from 2 to 6 carbon atoms, said composition containing less than1% water, encapsulated in gelatin.

2. An encapsulated synthetic liquid detergent composition at least 85active, the synthetic liquid detergent component of said compositionconsisting essentially of, by weight,

(a) 33-65% alkylarylsulfonic acid wherein the alkyl group contains from4 to 16 carbon atoms and the aryl group is benzyl, naphthyl or phenyl,

(b) 8-36.5% nonionic surface active agent, and

(c) 20-59% alkanolamine or alkylamine wherein the alkyl or alkanol groupcontains from 2 to 6 carbon atoms, said composition containing less than0.5% water, encapsulated in gelatin.

3. An encapsulated synthetic liquid detergent composition at least 85%active, the synthetic liquid detergent component of said compositionconsisting essentially of, by weight,

(a) 33-65% alkylarylsulfonic acid wherein the alkyl group contains from4 to 16 carbon atoms and the aryl group is benzyl, naphthyl or phenyl,

(b) 836.5% nonionic surface active agent, and

(c) 20-59% alkanolamine or alkylamine wherein the alkyl or lakanol groupcontains from 2 to 6 carbon atoms, said composition containing less than1% water and a small but significant amount up to 7.5% of anhydrousglycerol, encapsulated in gelatin.

4. An encapsulated synthetic liquid detergent composition at least 85%active, the synthetic liquid detergent component of said compositionconsisting essentially of, by weight,

(a) 33-65% alkylarylsulfonic acid wherein the alkyl group contains from4 to 16 carbon atoms and the alkyl or alkanol group contains from 2 to 6carbon (b) 8-36.5% nonionic surface active agent, and

(c) 20-59% alkanolamine or alkylamine wherein the alkyl or alkanol groupcontains from 2 to 6 carbon atoms, said composition containing 0.15-0.5%water and a small but significant amount up to 7.5% of anhydrousglycerol, encapsulated in gelatin.

5. An encapsulated synthetic liquid detergent as claimed in claim 1,wherein said nonionic surface active agent is an alkylaryl polyalkyleneglycol.

6. An encapsulated synthetic liquid detergent composition at least 85%active, the synthetic liquid detergent component of said compositionconsisting essentially of, by weight,

(a) 33-65% alkylarylsulfonic acid wherein the alkyl group contains from4 to 16 carbon atoms and the aryl group is benzyl, naphthyl or phenyl,

(b) 8-36.5% nonionic surface active agent selected from the groupconsisting of alkylaryl polyalkylene glycol laurylamide and laurylethoxylatc, and

() 20-59% alkanolamine or alkylamine wherein the alkyl or alkanol groupcontains from 2 to 6 carbon atoms, said composition containing less than1% water and a small but significant amount up to 7.5% of anhydrousglycerol, encapsulated in gelatin.

7. Process for preparing an encapsulated synthetic liquid detergentcomposition comprising dissolving an alkylarylsulfonic acid free fromfree acid wherein the alkyl group contains from 4 to 16 carbon atoms andthe aryl group is benzyl, naphthyl or phenyl, in benzene or toluene,adding a liquid nonionic surface active agent, heating the mixture underreflux until a homogeneous solution is obtained, subjecting the solutionto azeotropic distillation to remove water to a maximum of 1% by weightof the composition, removing the solvent by distillation under reducedpressure, and encapsulating the resulting composition in gelatin.

8. Process for preparing an encapsulated synthetic liquid detergentcomposition comprising dissolving an alkylarylsulfonic acid wherein thealkyl group contains from 4 to 16 carbon atoms and the aryl group isbenzyl, naphthyl or phenyl, in benzene or toluene, treating said acid toremove free acid, heating the resulting solution under reflux until ahomogeneous solution is obtained, subjecting the homogeneous solution toazeotropic distillation to remove water to a maximum of 1% by weight ofthe composition, removing the solvent by distillation under reducedpressure and encapsulating the resulting composition in gelatin.

9. Process as defined in claim :8, wherein said acid is treated toremove free acid by adding an alkylamine or an alkanolamine containing 2to 6 carbon atoms in the alkyl or alkanol group and allowing theproducts to react until a pH of 6.5 to 7.5 is obtained.

10. Process as defined in claim 9, which comprises adding a liquidnonionic surface active agent previous to heating under reflux.

11. Process as claimed in claim 10, which further comprises addinganhydrous glycerin before encapsulation.

12. An encapsulated synthetic liquid detergent as claimed in claim 1,wherein said nonionic surface active agent is a member selected from thegroup consisting of laurylamide and lauryl ethoxylate.

FOREIGN PATENTS 13,104 1894 Great Britain.

LEON D. ROSDOL, Primary Examiner W. E. SCHULZ, Assistant Examiner US.Cl. XR.

